Carburetor Adjustments - Shindaiwa 488EMC Owner's/Operator's Manual

Carburetor Adjustments

IMPORTANT!
A clean and unrestricted airflow is
essential to your saw engine's perfor-
mance and durability! Before attempting
any carburetor adjustments, inspect and
clean the engine air filter as required!
Procedures for maintaining your saw's air
filter are described on page 16 in this
manual.
Before starting the saw
I. Inspect saw chain tension, and
adjust if necessary.
2. Verify that the chain brake is
disengaged, and that the saw
chain is free to rotate.
Start the saw
Start the saw and warm the engine
to operating temperature. Place the
saw on the ground, and adjust the
carburetor as follows:
Idle speed adjustment
Use a screwdriver to slowly turn the
idle speed adjusting screw in or out
until the engine idles smoothly at
-1
2,600 - 3,000 rpm (min ).
Idle speed adjustment
Adjusting screw
WARNING!
The saw chain must never rotate at
engine idle speed.
Fuel mixture
adjustments
Low and High Mixture
Adjustments.
Low-speed mixture (engine idling
at operating temperature)
1. Using a small screwdriver, slowly
turn the low speed mixture screw
clockwise (lean mixture), and note
any changes in engine rpm.
2. Next, turn the low speed mixing
screw counter-clockwise (rich
mixture) and note any changes in
engine rpm.
3. Adjust the low speed mixture
screw to provide the smoothest
possible idle with no sacrifice in
acceleration.
4. If necessary, readjust the idle
speed screw for an engine idle
speed of 2,600 - 3,000 rpm (min
Low speed
adjustment screw
High speed adjustment screw
High speed mixture
1. No adjustment is necessary when
the saw is new.
2. After approximately 10 hours
running, readjust the H-needle to
1.0 turn (5 1/4 turns).
Low and High speed adjustment.
Standard opening.
L ......................... 1 ± 1/4 turns
H ......................... 1 ± 1/4 turns
"Standard opening" means number
of turns from the fully closed
position by turning needle gently
counter-clockwise
CAUTION!
Do not run saw at full throttle with no
load. If run in this condition, seizure
can occur.
CAUTION!
Do not adjust H-speed needle to less
than 3/4 turn. If run at less than 3/4
turn, seizure can occur.
-1 ).
11